- ID:
- ivo://CDS.VizieR/J/A+A/616/A124
- Title:
- NGC 3105 UBVR photometry
- Short Name:
- J/A+A/616/A124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- NGC 3105 is a young open cluster hosting blue, yellow, and red supergiants. This rare combination makes it an excellent laboratory for constraining evolutionary models of high-mass stars. It has been poorly studied, and the fundamental parameters such as its age or distance are not well defined. We intend to characterise in an accurate way the cluster and its evolved stars, for which we derive for the first time atmospheric parameters and chemical abundances. We performed a complete analysis combining UBVR photometry with spectroscopy. We obtained spectra with classification purposes for 14 blue stars and high-resolution spectroscopy for an in-depth analysis of the six other evolved stars. We identify 126 B-type likely members within a radius of 2.7+/-0.6arcmin, which implies an initial mass, Mcl~=4100M_{sun}_. We find a distance of 7.2+/-0.7kpc for NGC 3105, placing it at R_GC_=10.0+/-1.2kpc. Isochrone fitting supports an age of 28+/-6Ma, implying masses around 9.5M_{aun}_ for the supergiants. A high fraction of Be stars (~25%) is found at the top of the main sequence down to spectral type b3. From the spectral analysis we estimate for the cluster an average v_rad_=+46.9+/-0.9km/s and a low metallicity, [Fe/H]=-0.29+/-0.22. We also have determined, for the first time, chemical abundances for Li, O, Na, Mg, Si, Ca, Ti, Ni, Rb, Y, and Ba for the evolved stars. The chemical composition of the cluster is consistent with that of the Galactic thin disc. An overabundance of Ba is found, supporting the enhanced s-process. NGC 3105 has a low metallicity for its Galactocentric distance, comparable to typical LMC stars. It is a valuable spiral tracer in a very distant region of the Carina-Sagittarius spiral arm, a poorly known part of the Galaxy. As one of the few Galactic clusters containing blue, yellow, and red supergiants, it is massive enough to serve as a test bed for theoretical evolutionary models close to the boundary between intermediate- and high-mass stars.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/670/516
- Title:
- NGC 2547 4.5-8um photometry
- Short Name:
- J/ApJ/670/516
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have surveyed the 30Myr old cluster NGC 2547 for planetary debris disks using Spitzer. At 4.5-8um we are sensitive to the photospheric level down to mid-M stars (0.2M_{sun}_), and at 24um to early G stars (1.2M_{sun}_).
- ID:
- ivo://CDS.VizieR/J/A+A/437/457
- Title:
- NGC 2548 uvbyH{beta} and proper motions
- Short Name:
- J/A+A/437/457
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Deep CCD photometry in the uvby-H{beta} intermediate-band system is presented for the cluster NGC 2548 (M 48). A complete membership analysis based on astrometric and photometric criteria is applied.
- ID:
- ivo://CDS.VizieR/J/A+A/470/585
- Title:
- NGC 2682 uvby-Hbeta photometry
- Short Name:
- J/A+A/470/585
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Following deep astrometric and photometric study of the cluster NGC 2682 (M 67), we are able to accurately determine its fundamental parameters. Being an old and rich cluster, M 67 is relevant for the analysis of the Galactic disk evolution. M 67 is well studied but lacks a wide and deep Stroemgren photometric study. The brightest stars of the open cluster M 67 were used as uvby-Hbeta standard stars in our studies of NGC 1817 and NGC 2548, and the extension of the field covered, as well as the number of observations, allowed us to obtain the best set of Stroemgren data ever published for this cluster. We discuss the results of our CCD uvby-Hbeta intermediate-band photometry, covering an area of about 50'x50' down to V~19. Moreover, a complete membership segregation based on astrometric and photometric criteria is obtained. The photometric analysis of a selected sample of stars yields a reddening value of E(b-y)=0.03+/-0.03, a distance modulus of V_0_-M_V_=9.7+/-0.2 and [Fe/H]=0.01+/-0.14. Through isochrone fitting we found an age of logt=9.6+/-0.1 (4.2+/-0.2Gyr). A clump of approximately 60 stars around V=16, (b-y)=0.4 could be interpreted as a population of pre-cataclysmic variable stars (if members), or as a stream of field G-type stars placed at twice the distance of the cluster (if non-members).
- ID:
- ivo://CDS.VizieR/J/MNRAS/419/2379
- Title:
- NGC 6866 variables V and I light curves
- Short Name:
- J/MNRAS/419/2379
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of a variability search in the intermediate-age open cluster NGC 6866 from 29 nights over two observing seasons. We find 28 periodic variables, of which 19 are newly identified. The periods of these variables, which have V magnitudes from 11.5 to 19.3mag, range from ~48min to 37d. We detected several {delta} Scuti stars, some of which are of high amplitude, as well as {gamma} Doradus and rotational variables, and eclipsing binaries. In order to study the physical properties of the cluster, we obtained UBVRI photometry of all the stars on a good photometric night. The radial distribution of the stellar surface density shows that the cluster has a radial extent of about 7-arcmin ( ~3pc) with a peak density of 5.7+/-0.7stars/arcmin^2^ at the cluster centre. The colour-colour diagram indicates a reddening of E(B-V)=0.10mag towards NGC 6866. A distance of ~1.47kpc and an age of ~630Myr are estimated from the colour-magnitude diagram using the theoretical isochrones of solar metallicity.
- ID:
- ivo://CDS.VizieR/J/BaltA/12/323
- Title:
- NGC 1750 + 1758 Vilnius photometry
- Short Name:
- J/BaltA/12/323
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Seven-color photometry in the Vilnius system has been obtained for 420 stars down to V=16mag in the area containing the overlapping open clusters NGC 1750 and NGC 1758 in Taurus. Spectral and luminosity classes, color excesses, interstellar extinctions and distances are given for 287 stars. The classification of stars is based on their reddening-free Q-parameters. 18 stars observed photoelectrically were used as standards.
- ID:
- ivo://CDS.VizieR/J/BaltA/20/27
- Title:
- NGC 752 Vilnius photometry
- Short Name:
- J/BaltA/20/27
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have performed multicolor CCD observations of the central area of NGC 752 to search for faint, low-mass members of this open cluster. Four 12'x12' fields were taken on the 1.8m Vatican Advanced Technology Telescope (Mt. Graham, Arizona) using a 4K CCD camera and eight intermediate-band filters of the Stromvil (Stromgren + Vilnius) system. In this paper we present a catalog of photometry for 405 stars down to the limiting magnitude V=18.5, which contains V magnitudes and color indices of the Vilnius system, together with photometric determinations of spectral types, absolute magnitudes MV , interstellar reddening values E(Y-V) and metallicity parameters [Fe/H]. The good quality multicolor data made it possible to identify the locus of the lower main sequence to four magnitudes beyond the previous (photographic) limit. A relatively small number of photometric members identified at faint magnitudes seems to be indicative of actual dissolution of the cluster from the low-mass end.
- ID:
- ivo://CDS.VizieR/J/BaltA/19/35
- Title:
- NGC 752 Vilnius photometry
- Short Name:
- J/BaltA/19/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of CCD photometry in the seven-color Vilnius system of 3058 stars down to V~18.0mag in a 1.5 square degree field around the cluster NGC752 are presented. For most of the stars brighter than V=17.0mag, photometric spectral and luminosity classes are determined. The catalog of 1174 stars down to V=15.5mag is given in the paper. The entire catalog will be available at the CDS Simbad database. The color-magnitude diagram indicates an extension of the cluster's main sequence down to 5mag below the turnoff point.
- ID:
- ivo://CDS.VizieR/J/MNRAS/437/1628
- Title:
- NGC 7142 Vilnius photometry
- Short Name:
- J/MNRAS/437/1628
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of medium-band photometry of 1037 stars in the area of the old open cluster NGC 7142 down to V=20.1mag in the Vilnius seven-colour system are presented. Photometric results are used to classify in spectral and luminosity classes about 80 per cent of stars down to V=18.5mag, to identify cluster members, to determine the main cluster parameters and to investigate the interstellar extinction in this direction. The average extinction A_V_ of the cluster is about 1.1mag [E(B-V)=0.35], and its distance is 2.3kpc (the distance modulus 11.8mag). The age of the cluster, 3.0Gyr, is estimated from the intrinsic colour-magnitude diagram with individual dereddening of each star and the Padova isochrones. The surface distribution of the extinction is shown. The reddening of the eclipsing variable V375 Cep is found to be close to the average reddening of the cluster. Probably, the cluster contains five red clump giants, two asymptotic branch stars and four blue stragglers.
- ID:
- ivo://CDS.VizieR/J/MNRAS/438/1848
- Title:
- NGC 7129 Vilnius photometry
- Short Name:
- J/MNRAS/438/1848
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The dust cloud TGU H645 P2 and embedded in it the young open cluster NGC 7129 are investigated using the results of medium-band photometry of 159 stars in the Vilnius seven-colour system down to V=18.8mag. The photometric data were used to classify about 50 per cent of the measured stars in spectral and luminosity classes. The extinction A_V_ versus distance diagram for the 20'x20' area is plotted for 155 stars with two-dimensional classification from the present and the previous catalogues. The extinction values are found in the range between 0.6 and 3.4mag. However, some red giants, located in the direction of the dense parts of the cloud, exhibit the infrared extinction equivalent up to A_V_=13mag. The distance to the cloud (and the cluster) is found to be 1.15kpc (the true distance modulus 10.30mag). For determining the age of NGC 7129, a luminosity versus temperature diagram for six cluster members of spectral classes B3-A1 was compared with the Pisa pre-main-sequence evolution tracks and the Palla birthlines. The cluster can be as old as about 3Myr, but star formation continues till now as witnessed by the presence in the cloud of many younger pre-main-sequence objects identified with photometry from 2MASS, Spitzer and WISE infrared surveys.
